Replaced another typedef (shared_ptr<ISampleBuilder>).

This will allow us to notify the parent about changed parameter values.
Accompanying changes and problems:
- The default constructor ParameterPool() is deleted, to enforce
  presence of a parent.
- Therefore several tests had to be outcommented (marked as
  TEMPORARILY DISABLED). Improved tests should make more
  realistic use of ParameterPool, providing it an IParameterized* parent.
- The function IParameterized::getParameters() is outcommented.
  It was only used in some tests, and for printout. In printout
  functions, it is temporarily replaced by fixed text.

expand parameter_t (no typedef as alias for lengthy class names, except perhaps ocasionally at file scope)

Merge branch 'precompute' into develop - before starting to really work on the precomputation mechanism

Removed inclusion of FitKernel.h from FitSuite.
This required one nontrivial change: The pointer-to-implementation
must be a simple pointer, not a unique_ptr. If pimpl is a
unique_ptr, then no instance of FitSuite can be created without
knowing the size of FitKernel.